Sheku Bayoh was unconscious and in leg ­shackles and handcuffs when taken to hospital. Photograph: PA

Last Sunday, I took part in the funeral procession through Kirkcaldy of Sheku Bayoh. The 31-year-old local man, originally from Sierra Leone and a father of two, died in police custody on 3 May.

Like many others present, I did not know Bayoh. But what I had heard about the circumstances of his death – for instance, that he was clamped in leg shackles and handcuffs when taken unconscious to hospital, until medics insisted these restraints be removed – left me outraged at the way he and his family have been treated by the local police, the Scottish Police Federation and a seemingly indifferent Scottish government.

The exact circumstances of Bayoh’s death are swathed in mystery, and his family, along with the hundreds who gathered outside Kirkcaldy police station last Sunday for two minutes’ silence, want to know the truth. What is not disputed is that Bayoh was left unconscious after a pavement encounter with at first four, and then a further five, police officers, who used batons, CS gas and pepper spray, responding to reports that he had a knife.

The inquiry into Bayoh’s death by the Police Investigations and Review Commissioner – the Scottish equivalent of the Independent Police Complaints Commission in England and Wales – has been delayed for more than a month, because the officers involved, supported by their professional body, initially refused to give statements, and have only recently agreed to do so because his family have fought to raise awareness and put pressure on them.

How can any of us feel secure in our supposedly progressive Scotland, where police officers cannot be held to account?

At the public meeting after Bayoh’s funeral, his family’s solicitor, Aamer Anwar, cited “positional asphyxiation” as a possible cause of death. This is a terrifying term that is all too familiar to communities in the US and UK concerned about black people’s deaths in custody, when people are held face down with weight on top of them. “Black lives matter” and “I can’t breathe” have become familiar refrains, and now they resonate in the otherwise peaceful town of Kirkcaldy.

What chills me most is that the PIRC does not have the power to compel officers who are witnesses to attend interviews. Michael Matheson, the Scottish justice secretary, confirmed this week that officers’ obligation to give statements was decided on a “case-by-case basis”. He says that he will not intervene in the police investigation into Bayoh’s death, and has rejected calls for the PIRC to be given new statutory powers.

So the Scottish government hopes to let the Bayoh case drop; if that happens, Scotland’s police force would seem to be above the law. The motto of Police Scotland is “Keeping people safe”. But how can any of us feel secure in our supposedly progressive, politically engaged new Scotland, where police officers cannot be held to account?

This situation beggars belief. Any ordinary Scottish citizen involved in a violent incident would be expected to give a full and prompt witness statement. As one local woman asked in her letter to the local paper: “In what other walk of life, where someone dies in your care, would you be allowed to refuse to co-operate by providing details of what led up to the person’s death?”

In England and Wales, officers involved in any such incident would probably be sent on leave, without prejudice, once they had supplied full operational accounts of the event. Instead, the Bayoh family understands that the officers in question were allowed to meet in the police station for some time in the “golden hours” after the incident, the critical period for evidence-gathering.

The Bayoh family now faces a long, painful and expensive struggle to get some answers about his death. These answers may prove elusive until the Scottish government has the courage and honesty to accept that it must extend the PIRC’s powers, putting it on a par with its English and Welsh counterpart. If it fails to act, the case of Sheku Bayoh will leave an ugly stain on the face of Scottish justice.

This article was amended on Monday 15 June 2015. It originally said in the eighth paragraph: “Any ordinary Scottish citizen involved in a violent incident would be required to give a full and prompt witness statement.” However, there is no legal requirement to make such a statement, so “required” was changed to “expected”.